Photographic matrix



Sept. 3, 1935. L. T. y'rRoLANm A i 2,013,116

' PHOTOGRAPHIC MATRIX Filed oct. 2.1, 195o Patented Sept. 3, i935 Y i UNITED s TATEs PATENT OFFICE- rno'rocmlrmo Marnix i Leonard T. Troland, Cambridge, blass., assignor, by mesne assignments, to Technicolor, Inc., New York, N. Y., a corporation of Delaware Application october 21, 1930, serial No. 490,184

' 1s claims. (o1- iis-5.4)

The present invention relatestoaphotographic object iS a process of making lilms for cineprocess of making photographic prints, especially matography in natural colors Which requires a for use in the art of cinematography in natural minimum of material and labor and which uticolors, and to the films and matrices `used. in this lizes ,practically indestructible matrices. Other process and resulting therefrom. objects will be apparent from the following de- Various methods of making prints are known scrlption which refers to a drawing showing four whereby dyes are used to stain a photographicalsections through a film in various Stages 0f the ly produced gelatin record, that is a gelatin layer ProceSS to be described. which has varying properties relative to the abll- In order to obtain these objects I produce a ity of taking up dyes, thereby forming a record gelatin record which is relatively soft, in accord- 10 whether or not actually stained. such gelatin ance with the sradations of the picture, where records are also used for transferring dye to it has been exposed to light and which is exgelatin coated material according to the sotremely hard in the non-exposed parts. It hasy ca1led imbibition method.y The so-called pinaheretofore been proposed to soften the exposed 1'5 type, hydro-type and allied processes utilize parts of a silver emulsion, as for instance with` differentially hardened colloids, whereby the more ferrie Chloride- These processes, however, are exposed parts of an emulsion are hardened to a not Satisfactory in actual practice, lProbably begreater extent than the less exposed parts. The cause the softening iS not precededby a proper differentially hardened gelatin correspondingly treatment of the whole emulsion. In accordance takes-up, by absorption, adsorption or some other with the present invention the entire silver emulchemical or physical process, different amounts Sion layer iS Superhardened either prior to, or 20 of dye, no part of the original gelatin being reafter exposure, i. e. it is hardened to a much moved. higher degree than that o1' ordinary emulsions,

Matrices made according to these methods and the parte affected in varying degrees by the are in certain respects superior to relief matrices, light are softened in a manner peculiarly adaptespecially because the dye transfer from the lower ed for this Purpose, after the Silver record iS parts of a relief is not as perfect as from the developed. The invention will be better underhigher parts, which come into much better con- Stood from the following description of the gentact with the transfer blank. This causes' cereral idea'as Wellas of several concrete emboditain irregularities as for instance so-called dye ments illustrating the genus 0f the invention.

pools, which can be avoided by using a substan- Referring now to the drawing, Fig. l depicts an 30 tionally flat matrix. Another disadvantage of ordinary film with a base or support S and a silver relief matrices is the necessity of printing them gelatin emulSionE- Fig.- 2 ShoWS the Same illm .through the support which requires the use of after exposure, the Darts I of the emulsion havprojection printing machines which are in many ing been acted upon by the light under a photoc r respects less desirable than 'contact printers. graphic negative. Either Prior t0 exposure or d However, the nat matrices heretofore proposed after exposure and development the entire film have also certain disadvantages. They are not is hardened, as Shown irl Fig- 3; Where H repreas durable as might be desired and moreover sents the hardened emulsion, including the parts 40 require the making of master positives from the which have been exposed to light- Fig. 4 Shows original negatives since the dark parts of the the finished nlm after softening the emulsion at final picture correspond to soft parts of the gelathe image areas as described more fully below. tin and therefore `to dark parts of the record There are various means for hardening the emulfrom which the differentially hardened `gelatin sion, and I prefer for this purpose either chrome picture is made. Y alum or 4bichromates which are subsequently i It is the main object of the present invention treated with a suitable reducer, as for instance, t to produce a record made up of gelatin of varysulfur dioxide gas. However, other hardening ing hardness directly from a photographic negaagents, as for instance formaldehyde, pyrogallol, tive. Another object is to make such gelatin pyrocatechol, or hydroquinone may be used for records which are extremely durable, and which the same purpose. The hardening is to be con- 5o may be used either directly by staining up or as tinued until the Afilm is so extremely hard that it matrices for dye transfer. `Still another object becomes practically non-absorptive of dye. The is to make such gelatin records which reproduce parts of the emulsion which have been acted upon every detail sharply and well defined and which by the printing light are now softened by bathing o5 have practically clear high lights. .A further 'the film in agents which render thepreviously 5 extremely hard emulsion soft and capable of holding dye in proportion with the intensity or duration of the action of the light upon these parts. Although the specific details of the reactions and end products of gelatin with hardening agents are not known I assume that the hardening is due to the formation of an indenite compound of gelatin and the hardening agent. This compound, though it may vary in chemical composition depending on the nature of the hardening agent, is most likely specifically susceptible to reversal of the reaction by treatment with oxidizing agents in the presence of nely divided silver. It is not assumed that the softening is.the chemical equivalent of a reversal of the hardening reaction, but it is certain that the specific presence of silver localizes the softening to the areas which. c'ontain silver and that it -is therefore controlled in degree as well asextent by the amount of silver present in the exposed and developed emulsion. Without the presence of silver, this reaction, or series of reactions, might of itself produce results chemically equivalent in their ualitative aspect, to those of the present invv tion, which however utilizes these results for its purposes by specifically controlling them with the silver record. I found that any of the following oxidizing agents act as softeners, namely: potassium ferricyanide together with potassium permanganate; ammonium persulfate; bromide with hydrogen peroxide; or copper sulfate combined' with potassium bromide, nitric acid andl sodium perborate. In Fig. 4 the softened parts are indicated at S. After the softening has proceeded to the desired extent, the film ord parts in proportion to their softness, thereby directly producing a positive dye record since the softened parts which correspond to the more transparent parts of the negative from which the lm was printed will take up more dye than the other parts whereas the non-exposed parts will remain in their extremely hard condition, thereby assuring clear high lights. 'I'he differentially softened lm may also be used as a dye transfer matrix. For this purpose it is soaked in a suitable dye solution, the surplus dye washed off and the matrix then brought into contact with a colloid covered blank into which the dye transfers from the matrix in a manner well known in the art. The softer parts transfer more dye ,than the harder parts and the superhardened parts which are not atall affected by the softener will not transfer any dye, which again assures clear. high lights. It will also be understood by anyone skilled in the art, that this matrix can be used for printing from it with greasy ink, in

which case it would have to be exposed behind a positive. The printing process which involves the taking up of ink by the harder parts, and its- Coppel agents used for hardening after exposure as described, and softened after development in the same manner as if rhardened after exposure. .Hardening of the film before exposure has the following advantages: The penetration of the record and the resulting density distribution will be essentially restricted to the exposed surface of the emulsion, because the superhardened gelatin will tend to retard penetration ofchemical solutions and permit `the employment of'a developer of higher potential, thus ensuring a maximum closeness of packing of the silver per unit of optical density, the result being a reduction of graininess. The superhardened gelatin will also permit the use of higher temperatures during development and of agents in the developer which improve the nature of the silver grainsand/or the developing speed but which would soften ordinary soft gelatin to a degree making the use of such agents, e. g. strong ammonia, strong caustic soda, etc., hazardous or impossible.

In order to enable any one skilled in the art to carry out the above described process three embodiments will now be specifically described by Way of example.

First mamme-A silver record is produced upon an ordinary silver bromide -fllm by any known methods of exposure and development with non-hardening developers. 'I'he entire gelatin layer is then superhardened by bathing the film in concentrated basic chrome alum. The

film is then immersed in a bath of approximately the following composition:

Water 100 c. c.

Copper sulfate 2 grams Potassium bromide 0.1 gram Nitric acid 2 c. c.

Sodium perborate 5 grams This bath bleaches and softens the silver record quite rapidly. The resulting silver salts are then removed byflxation in ordinary sodium thio-sulfate. After having been washed the film may then be stained, as for instance with Kodachrome red or Pinatype blue D, which may either be retained in the film or which may be transferred to a gelatin coated blank.

Second mamma- The gelatin bearing the record in metallic silver is rendered very hard, for instance by bathing in chrome alum as above described. It ls then softened and bleached in the following solution:

This treatment softens the gelatin in correspondence with the density of the record. The film is then cleared by washing in dilute hydrochloric acid, subsequently immersed in an approximately solution of sodium blsulte in order to remove any remaining permanganate and is then fixed in ordinary fixing salt, washed and dried. The film may now be utilized as described above, either by staining it or by using it as a transfer matrix.

Third eample.-Anordinary silver bromide film is bathed for approximately flveseconds in a bath containing approximately 2 `grams of chrome alum to .100 c. c. water, a slight amount of ammonia being added in order to .neutralize to some extent the acidic character of the chrome alum solution. The film is then exposed, devel- 'opedand softened according to any of the methods above described, and mayalso be utilized either by staining or by using it asa transfer matrix. As already pointed out, temperatures and developing agents can be used for the development of the prehardened emulsion, which could not be applied to ordinary gelatin emulsions.

A dyed gelatin picture, or a transfer matrix made according to the present invention is much more durable than an ordinary differentially hardened matrix, since its hardest parts are considerably harder than thehardest parts of an ordinary matrix. This is due to the prehardening process which also renders the softer parts correspondingly more durable. A further result of the prehardening treatment is an extremely correct and sharp reproduction of all the details and gradations of the negative, and the lack of any objectionable matrix pattern in addition to the unavoidable silver grain pattern.

It should-l be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modications and equivalents which fall within the scope of the appended claims.

I claim:

l. The method of photographically making substantially at gelatin records which comprises uniformly hardening the whole record area of a, photographic silver emulsion and subsequently softening the parts affected by light and developed to constitute a silver record, under control by said record.

2.,The method of photographically making substantially fiat gelatin records which comprises uniformly treating the Whole record area of a photographic silver emulsion toa high degree of hardness and subsequently softening the parts affected by light in proportion with, and under control of the density of the developed silver record.

3. The method of making substantially flat matrices for dye printing which comprises making the entire record area of a photographic silver haloid emulsion substantially impervious to dyes by hardening it, exposing and developing the emulsion and softening the developed record in accordance with the action of the light, the

parts most affected by the light and constituting a silver record being softened to a greater extent -than the less affected parts under control of said record. l

4. The method of making substantially at dyed gelatin records which comprises treating a prehardened, substantially dye impervious gelatin layer containing a silver record in an agent containing ferricyanide and potassium permanganate, and subsequently dyeing said layer.

5. The method of making substantially flat gelatin records which comprises rendering a gelatin layer containing a positive silver record substantially .impermeable to dye by means of a hardener and subsequently differentially scftening the gelatin under control ofthe silver record.

6. The method of making substantially flat gelatin records which comprises rendering a gelatin layer containing a silver record substantially impermeable to dye by means of a hardener containing chromium compounds and subsequently differentially softening the gelatin under control of the silver image.

`'1. The method of making substantially fiat gelatin records which comprises rendering agelatin layercontaining a silver record substan tially impermeable to dye by means of a hardener containing chromium compounds and subsequently differentially softening the gelatin under control of the silver record in a bath containing an oxidizing agent.

8. The method of making substantially iatl gelatin records which comprises rendering a gelatin layer containing a silver record substantially impermeable to dye by means of a hardener containing chromium compounds and subsequently differentially softening the gelatin under control of the silver record in a bath containing hydrogen peroxide.

. 9. The method of photographically making substantially flat dye records which comprises rendering a gelatin layer containing a silver record substantially impermeable `to dye by hardening it and differentially softening the gelatin, the softening action being controlled as to degree Vand location by said silver record.

posed portions thereof under control of the silver record.

12. The method of making substantially iiat photographic gelatin records which comprises the steps of superhardening, exposing and developing a 'silver emulsion, and then softening and bleaching the exposed portions thereof under control of the silver record,

13. The method of making substantially fiat photographic gelatin records which comprises the steps of rendering a silver emulsion substantially impervious to dye and exposing it, then developing the latent image, treating it in an agent which differentially softens the gelatin under control of the silver record, and subsequently dyeing said emulsion.

14. The method of making substantially at photographic gelatin records which comprises the steps of rendering a silver emulsion substantially impervious to dye and exposing it, then developing the latent image, treating it in an agent containing an oxidizer which differentially lsoftens the gelatin under control of the silver record, and subsequently dyeing said emulsion.

15. The method of making substantially flat photographic records which comprises the steps of rendering a silver emulsion extremely hard, exposing anddeveloping it, and then treating said emulsion with an agent adapted to resoften the gelatin, the resoftening action being con-V trolled as to degree and location by the silver record contained in said emulsion.

16. The ,method of making substantially fiat photographic gelatin records which comprises treating a prehardened, substantially dye-impervious gelatin layer containing a silver image in an agent containing copper sulfate and potassium perborate.

' LEONARD T. TROLAND. 

